Thermal properties of 4-alkyl-4′-cyanostilbenes: a new series of liquid crystal compounds

The transition heats and temperatures of a series of 4-alkyl-4′-cyanostilbenes were measured with the DuPont 990 thermal analyzer. The entropies of both the solid-to-mesophase and the mesophase-to-isotropic liquid was found to be dependent on the number of carbons in the alkyl on the molecule. The entropy change in the nematic-to-smectic transition found in the C7 member of the series was found to be extremely small. © 1977.